1. Field of the Invention
This invention relates to an automatic ultrasonic testing apparatus for detecting flaws of structural balls, and more particularly to an automatic ultrasonic testing apparatus for structural balls which is capable of automatic and efficient detection of flaws in the structural balls.
2. Description of the Related Art
Tests on the outer surface and the interior of the structural balls for structural members have hitherto been made by an X-ray testing; by fluorescent penetrate testing or by examining the appearance of the structural balls under a microscope or with the naked eye.
In the X-ray or fluorescent penetrate testing or the inspection of the appearance under a microscope or with the naked eye, however, the object of testing, i.e., the ball structural for structural member is rotated manually and, therefore, much time is required for testing the entire peripheral surface of the ball. In addition, it is doubtful whether the entire peripheral surface of the ball can always be tested completely.
In order to overcome the drawbacks of the conventional testing methods mentioned above, one of the present inventors have previously proposed with other inventors, in U.S. patent application Ser. No. 07/311,041, now U.S. Pat. No. 4,969,361, (identified with Japanese Patent Application Laid-Open (KOKAI) No. 1-219554(1989)), an ultrasonic testing method and apparatus by which the entire peripheral surface of the ball can be tested by placing the ball on drive rollers and rotating the ball.
In the proposal of the ultrasonic testing method and apparatus disclosed in the U.S. Ser. No. 07/311,041 application, however, there is no concrete description of means for feeding the ball onto the drive rollers, only a description of holding the ball by the suction of an air cylinder.